With the increased use of portable electronic devices such as notebooks, portable telephones, cameras and others and with the increased use of electrically-driven automobiles, secondary or rechargeable batteries with high energy density have received increasing attention as a power source for these devices. Examples of such rechargeable batteries are lithium ion rechargeable batteries.
The demand for energy storage devices is further growing due to a growing production volume for electric vehicles and growing demand to store energy (e.g., renewable energy).
Energy density, i.e., how much energy can be stored in a battery, is important to reduce the weight and therefore the cost of battery materials and cost of battery movement. Therefore, it is of general interest to increase the energy density of batteries.